Vehicle occupant restraints include seat belts and actuatable occupant protection devices, such as air bags and seat belt pretensioners. The actuatable occupant protection devices are typically actuated in response to the vehicle experiencing deceleration above a predetermined deceleration. During a vehicle collision, for example, a controller in an occupant restraint system may determine which actuatable occupant protection devices are to be actuated. If an actuatable occupant protection device is to be actuated, the controller controls the actuation of the actuatable occupant protection device.
Actuation of an actuatable occupant protection device may further be controlled in accordance with a signal indicative of occupant usage of seat belts. If the seat belt is restraining the occupant, the air bag may be deployed differently than if the seat belt is not restraining the occupant. Also, when an occupant's seat belt is unbuckled, it is not necessary to deploy the seat belt pretensioner. Therefore, it is desirable to provide a signal indicative of whether the seat belt is buckled or unbuckled to the system controller. It is also desirable to provide a signal indicative of whether the seat belt is buckled or unbuckled to an indicator observable by the vehicle occupant to alert the occupant as to the status of the seat belt, i.e. buckled or unbuckled.